Vinylpyridine polymer adhesive composition containing boric oxide and a hetero-nitrogen compound as a stabilizer



rates VINYLP POLYlWER ADHESIVE COMPO- SITION CONTAG BORIC OXIDE AND A HETERO-NITROGEN CUP/WOUND AS A STA- BILIZER Gerard Kraus, Bartlesville, Okla, assignor to Phillips Petroleum Company, a corporation of Delaware No Drawing. Filed Nov. 1, 1957, Ser. No. 693,798

8 Claims. (Cl. 260-425) This invention relates to stabilized adhesive cement compositions. In a 'more specific aspect, the invention relates to fluidadhesive cement compositions comprising boric oxide dispersed in a polymer of a heterocyclic nitrogen base and containing certain heterocyclic nitrogen compounds as stabilizers.

It is known that good adhesive compositions can be made from either liquid orrubbery polymers of heterocyclic nitrogen bases by incorporating. boric oxide therein. The use of boric oxide improves the adhesiveness of such polymers. In some applications, the boric oxide is mixed with a solid polymer of the heterocyclic nitrogen base on a mill along with any other compounding ingredients. Such an intimate admixture can be used, for example, in the form of sheets having the desired dimensions. In a number of other applications, however, it is desirable to employ a liquid cement. men'ts can be made by mixing a liquid polymer of a heterocyclic nitrogenbase with boric oxide and any other."

desiredcuratives; or it can be made by mixing a solid,

semisolid or even a liquid polymer of the heterocyclic utility of dipping, spraying and the like is seriously impaired.

It is, therefore, an object of the invention to provide fluid adhesive cements comprising boric oxide dispersed ina polymer of a polymerizable heterocyclic nitrogen base having increased pot life. Other objects, as well as aspects and advantages, of the invention Will become apparent from a study of the accompanying disclosure.

According to the invention, there is provided a composition comprising a fluid adhesive cement containing boric oxide dispersed'in a polymer of a polymerizable heterocyclic nitrogen base as essential adhesive ingredicuts, and containing a nitrogen compound selected from the group consisting of pyridine, quinoline, isoquinoline, and one of the foregoing nitrogen compounds containing any number of aliphatic radicals selected 'from the group' consisting of saturated and unsaturated aliphatic radicals substituted for available nuclear hydrogen atoms of said nitrogen compound, the total number of carbon atoms in the total of said aliphatic groups not exceeding 20 carb on atoms and the total number of carbon'atoms in any one. aliphatic group not exceeding 12 carbon atoms,

. By the practice of this invention,'the pot life of such fluid adhesive cements can be increased from a few minutes for unstabilized cement to several days and even several weeks for the stabilized cement. The solutions, even after aging, have proved to be excellent for forming bonds between metals, plastics, rubber, wood, etc.

Such liquid ce-' The invention is applicable to any fluid adhesive cement comprising boric oxide dispersed in a polymer of a polymerizable heterocyclic nitrogen base as essential adhesive ingredients. The boric oxide improves the adhesive properties of the polymer. The invention is particularly advantageous with the boric oxide-heterocyclic nitrogen base polymer compositions disclosed and claimed in copending application Serial No. 666,232, filed June 17, 1957, by Herbert R. Anderson, Jr. Thus, a particularly important group of polymeric materials suitable for use in the preparation of the stabilized adhesive compositions of this invention are polymer products prepared by polymerization of as little as one part to as much as 70 parts by weight of an unsubstituted 'monovinylpyridine, alkyl-substituted monovinylpyridine, unsubstituted monovinylquinoline or alkyl-substituted monovinylquinoline with from 99 to 30 parts by weight of other monomers copolymerizable with the nitrogen base, based on 100 parts total polymerizable monomers. mers range from liquid to rubbery products.

The heterocyclic nitrogen base monomers generally preferredare those having not more than 12 carbon atoms in the nuclear-substituted groups other than vinyl or alpha-methylvinyl. Examples of such monomers include: 2-vinylpyridine; -4-vinylpyridine; 2,4,6-trimethy1- 5-vinylpyridine; 3,4,5,6-tetramethyl-Z-vinylpyridine; 3- ethyl-S-vinylpyridine; 2-vinyl-5-ethylpyridine; 2-methyl- S-vinylpyridine; 4,6-dimethyl-Z-vinylpyridine; 2,6-diethyl- 4-vinylpyridine; 2-isopropyl-4 vinylpyridine; 2-vinyl-5- ethylpyridine; 2-vinyl-5-propylpyridine; 2-vinyl-5-buty1- pyridine; 2-vinyl-5-hexylpyridine; 2-vinyl-5 hcptylpyridine; 2-methy1 5-undecy1-6-vinylpyridine; 2,4 dimethyl 5,6-clipentyl-3 vinylpyridine; 2 methyl 3,5 ditalphamethylvinyl)pyridine; 2-vinylquinoline; 2-vinyl-8 -ethylquinoline; 4-hexy1-5-vinylquinoline; 4-dodecyl-5 -vinylquinoline; 3,4,5,6-tetramethyl-Z-vinylquinoline; L-vinylisoquinoline; S-methyl-l-isopropenylisoquinoline, and the;

like.

Monomers copolymerizable with these heterocyclicynitrogen bases include compounds containing an active, CH =C group. Such compounds include styrene; substituted styrenes such as alkyl, alkoxy and halogen-sub methyl-S-vinylpyridine, acrylonitrile, and 1,3-butadiene. is a specific example of this type.

Broadly stated, the polymers employed as starting materials can be prepared by various methods known to the art, including mass and emulsion polymerization. Broadly, the polymers range from liquid to rubbery materials,-

the viscosity range being from 100 Saybolt Furol Seconds at 100 F. to a Mooney (ML-4) value of 150. A particularly useful class of polymers are rubbery polymers wherein a major amount of monomers comprise 1- or more conjugated diolefins. For such polymers, I prefer polymers prepared by polymerizing 3 to 25 parts by Weight ofthe vinyl-substituted heterocyclic nitrogen base. andv at least 50 parts byweight of a conugated diene per- This class of rubbery polymers includes terpolymers containing up to 25; percent of:

100 parts 'total monomers.

a comonomer containing a single vinylidene' group such as styrene; for example, such comonomers as are set-- forth in the description hereinbefore of the copolymeriza--' A specific example of such a rubbery terpolymer is one prepared by polymerizing'2-methylj-5-- vinylpyridine, 1,3-butadiene and acrylonitrile.

ble monomers.

The boric oxide employed in the practice of this inven- Patentecl July 12, 1960- Such poly-' inna oven. Boricracid does "HOLsgiVEI PmYBdQ adhesion. :Sodiinm metaborrate:likewisegives:nozincipronement in adhesion:

' 'ffibe ibnric ox'ide .i's: LHEeId L preferably; in :amozimtsasfromv Site: ltlspartsiby weightper l00rpartsrof polymer; larger annonntsi being. employed :as i the "nitrogen. .contentrofrthe; polymerz-increases- 'Ehecboric nxideLeanibe-msed' alone.

on xin adniixtnne with (carbon black 5,01! othemrpigments fillers, :SllGhZiElS'. clams-silica, titanium :dioxide. and

Therboric oxide-earlobe:usedealoneibut is often preferred to inclmlenother compoimding iingredientsr. tozprepare 1a:

suitableadhesive :stock.

Maniions :met-hods i'ot producing; the;- stabilized -:.compositionsi nflthis invention :can' be employed. Ln-Ione method, the-iheterocyclic nitrogen base stabilizer is-mixed with a-suitable solvent .for the polymer vsuchas benzene,

toluene-, xylene eyelohexane, chloroform, carbon tetra-- chloride, dimethylformid'e, mixtures :thereof, etc. Usually the-.--solvent employed has a boiling point below 400 ,F.,;althoughahigher boiling; solventoa-n beused. Totthessuspensionl resulting, the. boric oxide, other curatives,.- it.employedasueh as; sulfur, antioxidants, acceler- -ators-..and-.the like are added and ablend or'dispersion isrproduced. by.- milling,- stirring or .thelike. The. polymer or :asolutiomof;tbe.polymer isv then. blended WithJthe dispersion so-.that'-.a. -suspension of the desired composi.-- tion and; fluidity .is obtained; .In another. method, the polymer is dissolvecl in thesolvent-which contains-the. stabilizing. agent. dispersed therein,. and the boric oxide andlother. ingredients, ifemployed such as antioxidant, etc arenblended .intothe polymer solution. W11en-using ailiqnid polymer, thesolvent. can: be omitted, ifdesired, andrjthenstabilizer containing the bonicmxide can be blendedinto: the .liquid. polymer. A. less desirable method} for. preparing .the fluid adhesive cement. com-- position when employing a rubbery polymer'is to blend the. both: .oxide, the stabilizer. and the .polymeron a cooled rubber-milLor an internal.mixer,..such.ias. aBanbury mixer, and then dissolve the resultingpolymer. composition in-asolventjforthe polymer.

the ,practice of this invention, relatively small amounts otflthe stabilizer produce a beneficial efi'ect. Usually thereis employed about "I togabout 100 parts by"wei,gh t, preferably from about. to about. 50 parts; of stabilizer per 100 parts'by weight of polymer in the formulation. '1 In some cases, the amountsemployed when employing the higher ratios settforth are considerably in excess in-therequirements for stabilization, the excess servingas a solvent for the adhesive.

The stabilized. fluid adhesive compositions of this invention range from relatively non-viscous suspensions havingviscosities in the l to. 20 eentipoises'nange to relativelvviscous', thick fluids. Fluids which are:relatively fre'e flowin-g are preferred for-most applications. The viscosity can be adjusted, for instance, by'increasing or decreasingthe amount of solid polymer in-relation tothe solvent,-or 'lIl"Dl'l16 cases 'by adjusting the amount of the stabilizer: The amount of solvent employed" in the com positions can-be-greatly' varied depending'upon'the par ticular application for which the adhesive is-produce'd,

the particular solvent, the particular copol'ymer, etc., as

will understood, but in general-hem 2.5 to 200 parts bywei'ghrof-solvent per 1 part by'weight'of pol'ymer iswmployed -inthe case of arubbery polymer. Inthe case-'of'liquid polymers, the amountof solvent can be 4 amount of stabilizing agent in excess of that required for stabilization-as asolvent for the composition;

Examples of the defined -heterocyclic nitrogen compound stabil-izers applicable in accordance with this invention are Z-methylpyridine; 3-methylpyridine; 4-methylpyridine; 2,6-dimethylpyridi ne; '2,4,6-trirnethylpyridine; 2:ethylpyridine; .3-ethylpyridine; 4-.ethylpyridine; 2,6-diethyl'py'ridine; .-2,4,6-triethylpyridine; 2.-rnethyl-5-ethylpyridine-t Z-methyl-S-ethylpyridine; .2kv-inylpyri'dine;.4evinylvinylpyridine; 2=vinyl-;5-(ethylvinyhpyridine; .Z-vinyld- Water '180 1,3"-butadiene 75v 2'-methyl=5winylpyridine .25 Potassium fattyacid soap '6.0 40 KOH 0:1 KCl 011 sodium salt of condensed alkylzsaryl: sulfonic acid 0:3 K PgO 0.096 FeSOi-VHgO 0:083 Cumenehydroperoxide 0.050 Tert-dodecyli mercaptan 0.27:

propylpyridine; 2-vinyl-5-butylpyridine; 2-vinyl-S-hexylpyridine; 2-vinyl-S-heptylpyridine; 2-methyl-5-undecyl-6- vinylpyridine; 2,4 dimethyl-S,6-dipentyl-3-vinylpyridine; ZFmet-hyLBsS-di(alpha. .methylvinyl) pyridine; 2 vinylquinoline; Z-methykSwth-ylguinoline; 2 -v.inyl ---8-ethylquinoline; i-soq-uinoline;. 1-:Vinyl-isoquin01ine; 1+methylisoquinoline; S-metb-yl:leisopropenylisoquinoline; .2.-'nbutyl- 4vhexylpyridine; 2-dodecyl-5n-octylpyridine; 2-decy-l-5,6- isobutylpyridine; Z-ethyl-S-heptylpyridine; 2 methyl 5-- undeeyl-6=ethy;1pyridine; quinoline; 2-methyl-,6.-n-octyl-'8- isobntylquinoline; l-rdodecylisoquinoline; l ethylisoquinoline; S-ethy-Llahexadecylisoquinoline; andtthe. like.

The following .exangplesaare. merely illustrative of theinvention andashould. not. be interpreted "as limiting.

.EXAMBLE I- ='A. P0lyme'riza1iom0f*the"p0lymer.--A 15/25 copolymer'of 1 ;-3-butadi'ene= and z methyl fivinylpyridine was prepared"by emulsionpolymeriz-ation at41 F. using the. followingrecipe: I

Parts by weight After a 'reactionztime of. 14.5.1hours, the. reactionv was.

short stopped: at1a;conversion.ofv60'percent. The polymer was coagul-ated, dried and used for the tests-ade- SOlilZfQdrbfllOW.

;zB-..Preparation ohpolymersolution-Weighed amounts ofizthe: polymer.- were. dissolved. inwbenzene tog-ive in: solution'containing JO-percent' byweight .of the-;polymer. This solution was-used in conjunction with: the boric oxide.suspensions-described below. In all cases, sufficient bOl'iCl". oxide suspension'was. taken. to give 50 parts by weight of borieioxide per 1.00aparts of rubber.

=-.C.-.Preparution of-boriczoxidezdispersions-Boris oxide dispersions, herein'designated asdispersion A and B, were 1 prepared by. milling theftollowingl ingredients ina balbmill: (about 500mb capacity) for about two hours.

.Parts by Weight iiiriir 0' 0 18g; Santomm 0: 3(1- 0. 033 an it? Stabilizer; variable variablelilietermlneihbyidifierencsfhomtthe valneifound :fonthepercent, solids- (2 .5%)sdetermined.byzdry.ing asample otthedlsperslon at .100". O.

Eyridine or'z methyl isthylpyridine.

The stabilizers used in variable amounts, as indicated in the table were blended with these dispersions prior to use with the rubber solution. The pyridine and the 2- methyl-5-ethylpyridine blended readily with the suspensions. For the series of tests made with dispersion A, 30 grams of rubber solution was mixed with 8.50 grams of the dispersion to which the desired amount of stabili'zer' was added.

at a fixed rate and determining the maximum force in p.s.i. which was attained during stretching of the joint.

The results of the various shear tests which were made are summarized in Table I. This table also reports values for the pot life. These values were obtained by periodic observations of samples of the adhesive compositions. The pot life is defined as the time for the suspensions to become gelatinous or very viscous.

Table l V ADHESIVE COMPOSITIONS COMPRISING POLYMER AND BORIO OXIDE Stabilizer Adhesion m Shear, p.s.i.

Stabilizer, dispersion Pot Life Steel to Steel Polyethylene Parts/100 used interlayer Compound polymer None 6 min.-. None 0 min.-. 2-Methyl-5ethylpyridiu 12. 5 2 hours 2-Methyl-5-ethylpyridin 1 week- 950 2-Methyl-5-ethy1pyridine 16 hours. Pyridine 13.1 1 week- 1,030

1 The values under the columns headed with (a) were obtained with freshly prepared cement. The values under (0) were obtained with cement dispersions which had aged 2 days prior to use. 2 After the shear test it was observed that the joint had insufiicient adhesive.

For tests made with dispersion B, 33.3 grams of rubber solution was used with 13.36 grams of dispersion B. Thus, in all cases, the weight ratio of polymer to boric oxide was 2:0. In terms of parts per 100 parts of rubber, the adhesive compositions can be expressed by the D. Shear strength tests-Mild steel strips (20 gauge) which were 4 inches long and 1 inch wide were cleaned by etching in a solution prepared with 5 parts by volume of 36 N HNO3 and 100 parts by volume of 98 percent ethanol. These strips were used to fabricate lapped joints having an area of one square inch.

For the joints herein designated as a steel-to-steel joint, the adhesive compositions were brushed on the surfaces to be coated. Four coats were applied, each coat being allowed to air dry before application of the next coat. The lap joints were cured at 307 F. for minutes while applying a pressure on the order of 500 p.s.i. In this manner, a joint was formed having a thin (about 5 to 10 mil thickness) adhesive layer.

For the joints herein designated as having a polyethyl- 'ene innerlayer, two coats of the adhesive cement were brushed onto the steel strips which were air dried and were then dipped into a 10 percent solution of hydrogenated polybutadiene in trichloroethylene and dried. The steel strips were then assembled with an inner layer of a film of high density solid polyethylene of about 1 mil thickness. The joint was formed and cured at about 307 F. for 30 minutes, while applying only sufficient pressure to assure good contact.

Some joints were made with the adhesives immediately after mixing the rubber-solution with the boric oxide suspensions. For other tests the resulting mixture was aged two days before use to establish that the adhesive compositions did not deteriorate upon storage.

The shear strength of the joints were determined by placing the strips in tension, i.e., pulling on each strip The results in Table I show that by practice of this invention, the pot life can be increased from a value of less than 5 minutes to a week and even longer. The adhesive composition can be used immediately after mixing or after prolonged aging. The strength of the joints formed are not impaired by addition of the stabilizer.

As will be evident to those skilled in the art, various modifications of this invention can be made or followed in the light of the foregoing disclosure and discussion without departing from the spirit or scope of the disclosure or from the scope of the claims.

I claim:

1. In a fluid adhesive composition comprising a fluid adhesive cement containing boric oxide dispersed in a polymer of a monomer selected from the group consisting of an unsubstituted monovinylpyridine, an alkylsubstituted monovinylpyridine containing not more than 12 carbon atoms in alkyl-substituent groups, an unsubstituted monovinylquinoline and an alkyl-substituted monovinylquinoline containing not more than 12 carbon atoms in alkyl-substituent groups as essential adhesive in gredients, the improvement which consists of adding to the fluid adhesive cement a nitrogen compound selected from the group consisting of: (1) pyridine, (2) quinoline, (3) isoquinoline, and (4) one of the foregoing nitrogen compounds having any number of the nuclear hydrogen atoms of said nitrogen compound replaced by an aliphatic radical selected from the group consisting of saturated and unsaturated aliphatic hydrocarbon radicals, the total number of carbon atoms in the total of said aliphatic groups not exceeding 20 carbon atoms and the total number of carbon atoms in any one aliphatic group not exceeding 12 carbon atoms.

2. In a fluid adhesive composition comprising a fluid adhesive cement containing boric oxide dispersed in a polymer resulting from the polymerization of from 1 to 70 parts by weight of a monomer selected from the group consisting of an unsubstituted monovinylpyridine, an alkyl-substituted monovinylpyridine containing not more than 12 carbon atoms in alkyl-substituent groups, an unsubstituted monovinylquinoline and an alkyl-substituted monovinylquinoline containing not more than 12 carbon atoms in alkyl-substituent groups with from 99 to 30 parts by weight of another monomer containing an active CH =C group as essential adhesive ingredients, the improvement which consists of adding to the fluid adhesive cement alnitrogeneeompound. selected Lfrom ;tl1e

group-consisting of: 16.11 pyridine, '(12') quinoline, (3)- isoquinoline, A. 1013.6 of -.t-heforegoing :nitrogen compounds fhaving: anymumberoflthe nuelearrhydrogen atoms 1 of .said znitrogen ucomp'ound :replaced :by nan .;a1i-- phatic nadiealnseleetedafromiflre groupxzonsisting' of zsaturated rand unsaturated aaliphatic iliydrocarbon radicals,- the totai-rnumber-of searbonlzatomsiin rtotalof :sa-idaliphatic groups not exceeding 20 carbon atoms and the total number of carbon atoms in any one aliphatic group not exceeding 12 carbon atoms.

3. A composition of claim l wherein said polyniefis a polymer resulting from polymerizing 3 to 25 parts By Weight of said monomer with at least-1 50 parts by weight of a'conjugated' dine peri10Q parts%by-1weight of total" the groupconsisting of benzene; "toluene, xylene;,cyclo- 8" hexane; Ch'IOIGfGI'm; carbon: tetrachloride and dimethylform-amide. p

. 16. ..A :composition of ;claim- 53 :wherein: said adhesive cement contains a; {solvent for-said polymer selected oyelolziezean'e, zehloroform, carbonetetraehloride rand dimethylf'ormamidei 7. A composition of claim 4 wherein saidipolymerris an interpolymer of 2-methyl-5-vinylpyridine, 1,3-butadiene and acrylom'trile.

8. A composition of claim 3 wherein said polymer is 'aninterpolymer of Z-methyl-S-vinylpyridine and 1,3-

Bntad'i'ene;

References Cited in the file of this patent UNITED STATES PATENTS 2,136,788 Eairlie Nov. 15, 1938 7 2,422,153 Nimwegen et a1 June 10, 1947 2,530,174 KQeheetv a1. Nov. 21, 1950 2,619,445 Kalafus Nov. 25, 1952 .-2,748;097 fNied'erhauser May 29, 1956 

1. IN A FLUID ADHESIVE COMPOSITION COMPRISING A FLUID ADHESIVE CEMENT CONTAINING BORIC OXIDE DISPERSED IN A POLYMER OF A MONOMER SELECTED FROM THE GROUP CONSISTING OF AN UNSUBTITUTED MONOVINYLPYRIDINE, AND ALKYLSUBSTITURED MONOVINYLPYRIDINE CONTAINING NOT MORE THAN 12 CARBON ATOMS IN ALKYL-SUBSTITUENT GROUPS, AN UNSUBSTITUTED MONOVINYLQUINOLINE AND AN ALKYL-SUBSTITUTED MONOVINYLQUINOLINE CONTAINING NOT MORE THAN 12 CARBON ATOMS IN ALKYL-SUBSTITUENT GROUPS AS ESSENTIAL ADHESIVE IN GREDIENTS, THE IMPROVEMENT WHICH CONSISTS OF ADDING TO THE FLJID ADHESIVE CEMENT A NITROGEN COMPOUND SELECTED FROM THE GROUP CONSISTING OF: (1) PYRIDINE, (2) QUINOLINE, (3) ISOQUINOLINE, AND (4) ONE OF THE FOREGOING NITROGEN COMPOUNDS HAVING ANY NUMBER OF THE NUCLEAR HYDROGEN ATOMS OF SAID NITROGEN COMPOUND REPLACED BY AN ALIPHATIC RADICAL SELECTED FROM THE GROUP CONSISTING OF SATURATED AND UNSATURATED ALIPHATIC HYDROCARBON RADICALS, THE TOTAL NUMBER OF CARBON ATOMS IN THE TOTAL OF SAID ALIPHATIC GROUPS NOT EXCEEDING 20 CARBON ATOMS AND THE TOTAL NUMBER OF CARBON ATOMS IN ANY ONE ALIPHATIC GROUP NOT EXCEEDING 12 CARBON ATOMS. 